There has been known a humidity controller including a refrigerant circuit provided with adsorbent heat exchangers supporting an adsorbent thereon for adsorbing/desorbing moisture. The humidity controller performs air humidification or dehumidification by heating or cooling the adsorbent (e.g., see Patent Literature 1).
More specifically, Patent Literature 1 discloses a humidity controller including a refrigerant circuit provided with a compressor, a four-way switching valve, adsorbent heat exchangers and an expansion valve. Here, two adsorbent heat exchangers are included. In this humidity controller, a refrigeration cycle for circulating a refrigerant in the refrigerant circuit is performed when the compressor is actuated. The direction of refrigerant circulation flow is reversed at predetermined time intervals by the four-way switching valve serving as a switching mechanism because moisture adsorption and desorption by the adsorbent have to be repeated alternately. As a result, an operation in which one of the adsorbent heat exchangers serves as an evaporator and the other serves as a condenser and an operation in which the one of the adsorbent heat exchangers serves as a condenser and the other serves as an evaporator are repeated alternately. On the adsorbent heat exchanger serving as the evaporator, the adsorbent is cooled by the refrigerant and adsorbs moisture in the air. On the adsorbent heat exchanger serving as the condenser, the adsorbent is heated by the refrigerant and desorbs the moisture adsorbed thereon.
Patent Literature 1: Japanese Unexamined Patent Publication No. 2004-294048